In the gasoline and diesel-fuel industry, the quality of fuel being dispensed is of great importance. To assure that only clean fuel is dispensed into a customer's vehicle, filters may be positioned in the flow stream of fuel dispensers to remove dirt and solid particulates from the gasoline or diesel being dispensed. Also, water has been recognized as harmful to vehicle engines. For example, truck engines and auto engines that implement fuel injector systems are sensitive to water.
In recent years, alcohols such as Methyl Tertiary Butyl Ether (MTBE) and Ethyl alcohol (i.e., Ethanol) have been blended into gasoline to act as an oxygenate to reduce the amount of semi-combusted hydrocarbons that are discharged into the atmosphere by motor vehicles. However, several problems are created by blending alcohols with gasoline and diesel fuel. For example, MTBE's have been determined to be a potential contaminant to aquifers and well water due to their ability to resist biodegradation. Also, MTBE's are possibly hazardous as a carcinogen. Ethanol is a possible alternative to MTBE's, but attracts water more aggressively than MTBE alcohol. As a result, the amount of water that may be drawn into Ethanol-blended fuels is increased.
Regardless of the strong attraction to water, Ethanol blended fuels as high as eighty-five percent Ethanol to fifteen percent gasoline (E-85 Fuel) are being investigated for use in the fuel dispensing industry. Although other benefits may exist, the objective of fuels such as E-85 is to provide a fuel that reduces atmospheric pollutions over that produced from hydrocarbon fuels and to reduce dependence on foreign oil.
To promote the use of Ethanol blended fuel, the auto industry has begun producing engines capable of using both regular gasoline fuel and E-85 fuel. Also, the fuel dispensing industry has developed fuel dispensers capable of dispensing E-85 without rusting or otherwise damaging the dispensers. However, improvements in filtration technology are needed to effectively remove water from alcohol-blended fuels such as E-85.
Due to the chemistry of alcohol, a certain amount of water can be dissolved in an alcohol-blended fuel (i.e., the alcohol bonds with the water) creating alcohol-water molecules. These alcohol-water molecules are heavier than other molecules in the blended fuel and gradually descend. The descent of alcohol-water molecules can cause an uneven distribution of alcohol within a fuel tank (e.g., the fuel in the lower portions of the tank eventually have a higher concentration of alcohol and water molecules). The uneven distribution of alcohol in an alcohol-blended fuel is referred to phase-separated fuel. Also, if the water reaches a maximum amount that the alcohol-blended fuel can dissolve, any additional water will separate from the blended fuel as phase-separated water and eventually settle at the bottom of the tank.
There are several problems that are caused by water. First, the creation of alcohol-water molecules degrades the performance of the blended fuel. Second, the heavier alcohol-water molecules cause an uneven concentration of alcohol in a blended fuel (i.e., phase-separate fuel) which causes lower burn temperatures (e.g., temperatures produced by a fuel containing less alcohol than expected) and higher burn temperatures (e.g., temperatures produced by a fuel containing more alcohol than expected). A lower burn temperature increases pollutants and a higher burn temperature is potentially damaging to engine parts. Third, phase-separated water acts as an abrasive causing damage to engine parts.
Existing water filters implement water-absorbing polymers having an anionic (negative) valence. These water-absorbing polymers attract and bond with the cationic (positive) valence of the water (H2O) molecules that are passing through the water-absorbing media of the filter. However, in alcohol-blended fuels, the alcohol (due to its strong negative valence field) is repulsed by the negative valence field of the water-absorbing polymers. The combined influence of the covalent bond between alcohol-water molecules and the repulsion of the alcohol molecules from the water-absorbing polymers prevents current water-absorbing polymers from filtering (i.e., removing or retaining) water effectively.
Another problem with existing filters is that the water-absorbing polymers are derived from organic biomass such as cornstarch or cellulose with a methacrylic or other acid to form the water-absorbing polymers. The organic base of these water-absorbing polymers is subject to being degraded by bacteria and other microorganisms (i.e., life forms) that are normally found in water that is in gasoline or diesel storage tanks. The carbohydrate (starch) portion of these polymers acts as a food source that allows the life forms that are in water to proliferate within the filter. These life forms can disarm the filter's ability to remove water from fuel or to hold water that had previously been removed.